<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script>
			var username,age;  //全局变量
			age=35;
			salary = 100; //局部变量
			console.log(age)
			console.log(salary)
		</script>
	</body>
</html>